What sanctions? I've never seen one even fined for pirating software or any other kind of media, let alone someone fined for decompiling or altering software in general. Is something that everyone does.
The only thing that can get you into trouble is if you that kind of things for a profit, and that is right, but if you do that for personal use or to share it on the internet without profiting for it, nobody will ever do you anything...
Does Aaron Schwartz count as a counterexample? I realize he was never formally convicted but they were in the process of throwing the book at him when he died.
The only thing that can get you into trouble is if you that kind of things for a profit, and that is right, but if you do that for personal use or to share it on the internet without profiting for it, nobody will ever do you anything...